Freeze, Popup In Firefox On Monterey

This morning on this Mac Monterey I had so much trouble accessing the Etsy site that I had to get on my newer Windows 10. In this browser, I opened a tab and a popup occurred that advised me to download an addon for safe browsing. After backing out I tried again to get to Etsy when more popups occurred, with audio, freezing the system to where I had to use the power button. A woman's voice said that I was going to a malicious site, and in the lower right corner gave the Apple telephone number. Underneath the popups the Apple site shown, which may have been counterfeit. I emailed Etsy from my Windows 10 about this. Is there any validity to this; or is somebody making a strong sales pitch to get me to download something under the guise of security? Under Windows 10 I used Firefox and the problem did not occur.